A typical fossil fuel power plant, described for example in EP 2351914 A, has a boiler comprising an economizer, an evaporator, a super heater, and a reheater, as well as several steam turbine modules comprising high-pressure, intermediated-pressure and low-pressure stages mounted on a shaft that drives a generator. Steam generated by the boiler is first expanded in the high-pressure turbine stage after which it is reheated in the reheater before being subsequently fed into the intermediate-pressure turbine stage. Steam exhausted from the intermediate stage, after being further expanded in the low-pressure turbine stage, is fed into a condenser. Condensate collected in the well of the, condenser is pumped by one or more extraction pumps to condensate preheaters that preheat the condensate using steam extracted from the low- and intermediate-pressure steam turbines. The plant may further comprise one or more high pressure preheaters located downstream of a feed water pump system used to boost the pressure of the condensate downstream of the low-pressure preheaters. Steam extracted from the high pressure turbine stage may be used as a heat source for these preheaters. Preheated condensate from the high pressure preheaters is then feed into the boiler/ economiser thus completing a closed loop steam condensate cycle.
A typical fossil fuel power plant includes a fossil fuel system, which may comprise a coal milling facility that feeds the coal into the boiler, an air system for supplying combustion air, and a flue gas exhaust system for directing flue gas from the boiler. The flue gas system typically includes an air preheater for preheating air before it enters the boiler and a particulate collection system, such as an electrostatic precipitator or fabric filter and a desulphurization unit that polishes the flue gas before it is emitted through a stack or cooling tower. Preheating of air using flue gas is one means of improving the thermal efficiency of the plant. There is, however, a constant need to provide plants that balance increasing thermal efficiency demands at reduced cost which may be achieve through reduced complexity.